Iberdrola's commitment to hydroelectric generation goes back to the company's early days, over 100 years ago. Nowadays, it means the company's installed capacity in Spain is 8,807 megawatts (MW), divided up among some 140 power plants.

In 2013, the company's output amounted to 14,795 gigawatt hours (GWh), a major (63.7%) increase on the previous year because of the high water availability recorded in the period. This amount also represents 33.5% of the total energy generated by Iberdrola in Spain in the year.

The company has commissioned new hydroelectric facilities in Spain in the last year, thereby increasing its capacity. This new input follows the commissioning of new generators at the La Muela and Santo Estevo complexes (in the Valencia and Galicia regions, respectively).

The Cortes-La Muela complex, with an installed capacity of 2,000 MW, is now the largest pure pumped storage facility in Europe, with the ability to generate some 5,000 GWh per year. The construction of this clean energy plant located in the Júcar river basin had a major impact throughout its area of influence. The overall investment amounted to over €1.2 billion and thousands of jobs were created.

Iberdrola also commissioned the Santo Estevo II plant in the Sil river basin in 2013. With a capacity of 176.9 MW, this facility optimises the existing infrastructure: dam, reservoir, substation and transmission lines. It is now the largest hydroelectric complex in this autonomous region, with an installed capacity of 441 MW and an estimated output of over 1,000 GWh per year.

This new power plant was one of the company's flagship engineering projects in recent years. The design is entirely underground and the facility is housed in a cavern to ensure that it blends in with its natural surroundings.

Iberdrola's commitment to hydroelectric technology is part of its pledge to promote an energy that is 100% renewable and free from air pollutant emissions, one that can reduce our dependency on foreign energy suppliers and which is also capable of meeting the needs of the demand in real time: in short, a fundamental tool in increasing security and guaranteeing the electricity supply.